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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Monolithic Power Systems Inc. MPQ28261DL-LF-Z

Name: MPQ28261DL-LF-Z
Brand: Monolithic Power Systems Inc.
SKU: MPQ28261DL-LF-Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPQ28261DL-LF-Z

Manufacturer:: Monolithic Power Systems Inc.

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 14-VFDFN Exposed Pad

Datasheet:: MPQ28261DL-LF-Z.pdf

Description:: IC REG BUCK ADJ 3A 14QFN

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Product details

Overview

MPQ28261DL-LF-Z from Monolithic Power Systems is a synchronous step-down DC/DC converter with integrated 120mΩ high-side and 20mΩ low-side MOSFETs, delivering up to 3A continuous output current across a 4.5V–21V input range. It operates at a fixed 500kHz switching frequency, features external soft-start control via SS pin, power-good (PG) open-drain output, and supports adjustable output voltage from 0.603V to 18V. It is used in DSL/cable modems for efficient local 1.2V/3A rail generation.

For engineers reviewing the MPQ28261DL-LF-Z datasheet, MPQ28261DL-LF-Z pinout, MPQ28261DL-LF-Z application, or MPQ28261DL-LF-Z equivalent, key selection criteria include input voltage range compatibility, thermal performance in QFN14 (3×4mm), PG signal timing relative to soft-start, current-mode loop stability, and MOSFET R_DS(on) impact on efficiency at 3A load.

Technical Context

The MPQ28261DL-LF-Z employs peak-current-mode control with a fixed 500kHz oscillator, enabling fast transient response and inherent loop stabilization. Its internal error amplifier compares FB voltage against a 0.603V reference and drives COMP to regulate duty cycle via HS-FET on-time control.

It integrates a 5.1V VCC regulator powered from VIN, bootstrap circuitry for high-side gate drive, and independent protection blocks: hiccup-mode over-current protection triggered at ≥4.2A, thermal shutdown at 150°C with 25°C hysteresis, and input UVLO with 4.0V rising threshold and 880mV hysteresis.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	4.5V to 21V - supports wide industrial and telecom supply rails including 5V, 12V, and 19V adapters.
Output Current	3A continuous - sustains full load without derating at T_A ≤ 70°C with proper PCB thermal design.
Switching Frequency	Fixed 500kHz - enables compact magnetics (e.g., 2.8µH inductor) and predictable EMI profile.
Feedback Reference	0.603V ±3mV - sets output accuracy; allows precise 1.2V regulation using 10kΩ/10kΩ resistor divider.
HS/LS R_DS(on)	120mΩ / 20mΩ - determines conduction loss; achieves up to 85% efficiency at 12V→1.2V/3A.
Soft-Start Control	External capacitor on SS pin - programs start-up time (e.g., 100nF → 5ms); prevents inrush into large output caps.
Power-Good Output	Open-drain PG with 90%/80% V_FB thresholds - provides system sequencing signal with ~¼ SS delay.

Pinout & Package

MPQ28261DL-LF-Z is housed in a thermally enhanced 3mm × 4mm, 14-pin QFN package with exposed thermal pad (pins 12–13). The package requires soldering the exposed pad to a solid GND plane for optimal thermal resistance (θ_JA = 48°C/W, θ_JC = 11°C/W).

Pin/Terminal	Circuit Role	Design Meaning
1 IN	Main power input	Accepts 4.5V–21V; must be decoupled with ≥22µF low-ESR ceramic capacitor placed adjacent to pin.
2–5 SW	Switch node	Drives external inductor; carries high di/dt; requires short, wide traces and multiple vias to GND.
6 BST	Bootstrap supply	Connects to SW via 0.1µF ceramic capacitor; powers high-side gate driver; optional external diode improves efficiency at high duty cycles.
7 EN	Enable control	Active-high logic input with 1MΩ internal pull-down; 1.3V typical enable threshold; supports automatic startup via resistive divider from IN.
8 FB	Feedback sense	Monitors output via resistor divider; connects to error amplifier non-inverting input; trace must avoid SW/BST noise.
9 PG	Power-good indicator	Open-drain output; pulled high by external resistor when V_OUT reaches 90% of regulation; delays ~¼ SS time.
10 SS	Soft-start timing	Internal 12µA current source charges external capacitor; voltage ramp controls output voltage rise rate.
11 VCC	Bias supply	~5.1V regulated output; powers internal circuitry; requires 0.1µF ceramic decoupling close to pin.
12–13 GND	Thermal & power ground	Exposed pad; must be connected to PCB GND plane with ≥4 thermal vias for thermal management.
14 AGND	Signal ground	Separate analog ground; must be tied to GND on PCB (not internally connected); minimizes noise coupling into FB path.

Key Features

Feature	Design Value
Synchronous rectification	Integrated 120mΩ HS + 20mΩ LS MOSFETs eliminate external Schottky loss, enabling >85% efficiency at 12V→1.2V/3A.
Current-mode control	Peak-current sensing provides inherent cycle-by-cycle current limiting and stable loop response without external compensation.
Programmable soft-start	SS pin accepts external capacitor (e.g., 47nF → 2.35ms) to limit inrush current and prevent output overshoot during startup.
Power-good signaling	PG pin asserts after V_OUT stabilizes to 90% of target, with built-in delay synchronized to SS ramp-enables reliable system sequencing.
Fault protection suite	Hiccup OCP (4.2A min), thermal shutdown (150°C), and input UVLO (4.0V rising) provide robust fault recovery without latch-off.

Applications

DSL Modem Power Rail

Cable Modem Core Supply

Use Scenario: Generating stable 1.2V/3A core voltage for Broadcom BCM3383 SoC in residential DSL modems operating from 12V adapter.

IC Role / Device Role / Timing Role: Primary synchronous buck regulator; regulates output under dynamic load steps up to 2A/µs; PG signals SoC reset release after soft-start.

Use Value: Integrated MOSFETs and 500kHz operation reduce BOM count and board area vs. controller+discrete solution; 0.603V reference ensures tight 1.2V tolerance.

Use Scenario: Providing 3.3V/2.5A auxiliary rail in DOCSIS 3.0 cable modems powered from 19V wall adapter.

IC Role / Device Role / Timing Role: Secondary buck converter; configured with R1=10kΩ/R2=2.2kΩ for 3.3V; SS capacitor set to 33nF for 1.65ms ramp.

Use Value: Wide 4.5V–21V input accommodates adapter tolerance and line drop; PG output coordinates FPGA configuration timing with power rail stability.

Set-Top Box SoC Core

Telecom Line Card Bias

Use Scenario: Delivering 1.0V/3A to ARM-based media processor (e.g., STi7105) in IPTV set-top boxes with 12V backplane supply.

IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator; uses T-network feedback (R1=10kΩ, R2=15kΩ, Rt=24kΩ) for accurate 1.0V setting.

Use Value: Low 20mΩ LS R_DS(on) minimizes dropout loss at light loads; thermal shutdown protects during enclosure airflow restriction.

Use Scenario: Generating 5.0V/2A bias for analog front-end (AFE) and PHY ICs on telecom line cards powered from -48V DC/DC intermediate bus.

IC Role / Device Role / Timing Role: Intermediate buck stage; accepts 12V derived from -48V; PG output enables AFE clock distribution only after regulation.

Use Value: 21V absolute max rating tolerates 12V rail transients; 1% reference accuracy maintains ADC reference stability across temperature.

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down converter applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP2315DJ-LF-Z	Lower 17V max input, 2A output, same 3×4mm QFN but 8-pin; no PG or SS pins.	Lacks power sequencing support; suitable only for non-critical 2A rails where soft-start and PG are unnecessary.	Select only if cost sensitivity outweighs need for PG signaling and 3A capability.
TPS54331DR	TI part: 28V input, 3A, adjustable frequency (100kHz–2.5MHz), external FETs required.	Requires external high-side/low-side MOSFETs and compensation network; higher BOM count and layout complexity.	Choose when frequency tuning or higher input voltage margin (>21V) is mandatory, accepting added design effort.

Compared with MPQ28261DL-LF-Z, MP2315DJ-LF-Z sacrifices PG/SS functionality and current rating for lower cost, while TPS54331DR trades integration for flexibility in frequency and input range-neither offers the same balance of 3A capability, PG/SS, and full integration in a 14-pin QFN.

Availability

MPQ28261DL-LF-Z is available at Aetrix Electronics and suitable for DSL modems, cable modems, and set-top boxes requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MPQ28261DL-LF-Z includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with design centers in the US, China, and Taiwan.

The MPQ28261 belongs to MPS's MPQ-series of integrated synchronous buck converters, engineered for space-constrained, high-efficiency DC/DC conversion in broadband communications and consumer electronics.

FAQ

What is the minimum recommended input capacitance for MPQ28261DL-LF-Z?

The datasheet specifies a 22µF low-ESR ceramic capacitor (e.g., X5R/X7R) placed directly at the IN pin, supplemented by a 0.1µF ceramic capacitor near the IC. This combination handles RMS input ripple current up to 1.5A and limits voltage ripple to <100mV under 3A load at 500kHz, ensuring stable operation and minimizing EMI.

Can MPQ28261DL-LF-Z operate with a 3.3V input supply?

No. The absolute minimum operating input voltage is 4.5V per the Recommended Operating Conditions table. At 3.3V, the internal VCC regulator cannot sustain 5.1V bias, UVLO remains active, and the device will not enable-even if EN is asserted-due to insufficient headroom for bootstrap charging and gate drive.

How does the hiccup over-current protection behave during startup?

Hiccup OCP is active during soft-start. If output voltage drops below 70% of target and inductor current exceeds 4.2A, the IC disables switching, discharges the SS capacitor, and restarts soft-start after a brief recovery interval. This prevents thermal runaway during short-circuit faults before regulation is established.

Is an external bootstrap diode required for MPQ28261DL-LF-Z?

An external bootstrap diode (e.g., 1N4148) from VCC to BST is optional but recommended when duty cycle exceeds 65%-typically at V_OUT ≥ 3.3V with V_IN ≤ 5.5V. It improves high-side gate drive strength and efficiency by reducing BST capacitor discharge through internal paths.

What is the maximum output capacitance supported by MPQ28261DL-LF-Z?

The device supports up to 1100µF output capacitance, validated with 3A load step testing. Larger values require proportionally larger SS capacitors to maintain controlled rise time and avoid current-limit triggering during startup due to excessive inrush into the bulk cap.

How is thermal performance affected by PCB layout of the exposed pad?

Thermal resistance θ_JA degrades from 48°C/W (4-layer board, 4 thermal vias) to >75°C/W with inadequate pad connection. The exposed pad (pins 12–13) must be soldered to a solid internal or bottom-layer GND plane using ≥4 vias (0.3mm diameter) to maintain junction temperature ≤125°C at 3A/12V→1.2V.

Does MPQ28261DL-LF-Z support pre-biased output startup?

Yes. When V_OUT is pre-biased, the IC inhibits switching until the SS voltage exceeds the sensed FB voltage. This prevents reverse current flow through the low-side MOSFET and avoids output collapse, enabling safe hot-swap or rail-sequencing scenarios.

MPQ28261DL-LF-Z Specifications

Product attributes: Attribute value

Manufacturer:: Monolithic Power Systems Inc.

Series:: -

Package/Case:: 14-VFDFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Active

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 4.5V

Voltage - Input (Max):: 21V

Voltage - Output (Min/Fixed):: 0.603V

Voltage - Output (Max):: 18V

Current - Output:: 3A

Frequency - Switching:: 500kHz

Synchronous Rectifier:: Yes

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-QFN (3x4)

MPQ28261DL-LF-Z FAQ

1.How can I place an order for MPQ28261DL-LF-Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MPQ28261DL-LF-Z on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MPQ28261DL-LF-Z reliable?

The price and inventory of MPQ28261DL-LF-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPQ28261DL-LF-Z is usually 5 days.

3.What payment methods are accepted for MPQ28261DL-LF-Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPQ28261DL-LF-Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPQ28261DL-LF-Z?

MPQ28261DL-LF-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPQ28261DL-LF-Z order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MPQ28261DL-LF-Z?

For technical support, including MPQ28261DL-LF-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPQ28261DL-LF-Z requirements.

6.How does Aetrix verify that MPQ28261DL-LF-Z is sourced from the original manufacturer or authorized distributors?

All MPQ28261DL-LF-Z products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MPQ28261DL-LF-Z meets industry standards.

7.What is the process for return or replacement of MPQ28261DL-LF-Z?

All MPQ28261DL-LF-Z units undergo pre-shipment inspection (PSI). If there is an issue with MPQ28261DL-LF-Z, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MPQ28261DL-LF-Z part is unused and in its original packaging.

Return procedure for MPQ28261DL-LF-Z:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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